The Arts, Sciences and Medicine: Aircraft LANDINGS Made Easy

Saturday, July 21, 2018

Aircraft LANDINGS Made Easy

Let us talk about landing an aircraft, shall we?

Apparently from what I seem to find when flying with another person and even with another pilot, nothing seems so satisfying as greasing the landing. The rest of the flight blurs and is captured into this singularity called landing. You might have dodged a thunderstorm, you might have experienced a wind shear, you might even have encountered a gusty crosswind, but if, and that is the biggest if, if you didn’t chirp the landing, well then, you just displayed your incompetence.

In fact, several weeks ago, I was a passenger in seat 29A in a B737 on a very gusty day, landing at KEWR. The pilot up ahead behind the bolted doors must have been very good, he touched down smoothly without a lurch. Hmm… I thought, I had fallen into the same trap? Actually no. You see most of the flight on this large aluminum tube was on the triple redundant autopilot, but the landing was definitely the pilot’s, so he gets the award.

On the other hand in our tinier aluminum or composite bodied transportation devices, we can and do use “George” at cruise and sometime through descent but once in the 5-mile vicinity of the airport, it is all on the left seat driver. To put it gently, “You’re it!”

Consider approaching the 45-degree entry for the downwind. It is important to scan traffic and look at the departure end of the runway for traffic and potential landing zones if on a later flight the engine decides to pull a fast one. (VSO specified in this example as 60 kts – adjust Vso and tailor the advice to your specific aircraft accordingly). So on 45-degree approach to runway, Speed Vso * 1.6 (in most cases 95-100kts). Stabilized with the appropriate power settings. Left downwind stabilized at 1000 feet (midfield) above the runway threshold keep the speed to VSo *1.5 (In most cases 90-92 kts). Turning Base reduce to Vso * 1.4 (in most cases between 82-85 kts). Turning final reduce power for Vso *1.3 (in most cases 78 kts). The last 500 feet on final are a matter of experience and practice. In short field approaches reduce speed to Vso *1.2 ( in most cases 72 kts).

Ok, ok, I realize the above rhetoric looks kind of pedantic, but now here is the key to the puzzle. Let’s say you are in a Cessna 172 or Archer aircraft where the power settings are by means of the RPM only. The trick is to set the power setting to the most appropriate setting (Maybe 1600-1700 RPM) and then use the flap settings to realize the speed reductions. This is easily done at altitude on level flights. Go out there in the wild blue and practice this to figure out at LEVEL ALTITUDE say around 1000-2000 feet and see what the aircraft delivers. Start with 2000 RPM and reduce your way to 1500 RPM with increasing flap settings to realize the speeds the aircraft delivers, to figure out what works for the aircraft you are commanding. Once the appropriate speed is determined. Write the power settings and configurations down and voila you have a winning strategy. In the Arrow , Mooney, Bonanza and other Manifold (MP) yielding complex aircraft the idea is similar but slightly different. Establish the power setting with a 17 MP and a 2400 RPM (should get you to gear speed) Put the gear down and trim for level flight and then use the flaps for future speed reductions. Further reduction in power starts at 500 feet on final. Hmm…QED.

Flaps are a great addition to the wings; they provide drag and 30 degree flaps essentially are like barn doors that decrease air speeds and allow us to fly deeper descents to the field without increasing the air-speed. Pretty smart thinking by Edward F. Zaparka in 1932. They also by virtue of the increased camber of the airfoil (wing) help reduce the stall speed. A double advantaged whammy, so to speak. Lower Airspeeds, Lower Stall speeds and viola you can hover down to a chirper landings...most of the time. Except that one time when the Airbus 321 pilot decided to flair 10 feet above the runway and darn near took my teeth out. I can still some days hear that chatter.

Nuance: In gusty winds add HALF the gust (say 320 10G20) or 5 kts to your speed by adjusting upwards the MP or RPM as the case maybe.

Another nuance: The Dreaded, sweaty and bile eating last 500 feet. How do we address that? Simple. My dear Watson!

The power is in your hand. Get your aircraft visually aligned with the runway. Put the nose of the aircraft right on the approach end of the runway and KEEP it there (as if you are in a shallow dive), now adjust the power (MP or RPM) to maintain the Vso *1.3 till you know you have the runway made (which means in case of complete loss of power at that altitude, you can glide to a safe landing on to the runway). But please make sure if this format is different than your instructor’s advice, practice what your instructor says and if any of the above is helpful to your thought process, incorporate while he or she is stuck in the right seat.